In recent years, many types of stoplight switches for stoplight control are used in which, in order to assure lighting of a stoplight at the time a brake pedal of a vehicle is depressed and going off of the light when released, the length of the action rod of the switch can be adjusted after being mounted on a bracket disposed opposite the brake pedal.
Referring to FIG. 9 and FIG. 10, a description will be given on such a conventional stoplight switch.
FIG. 9 is a cross-sectional view of a conventional stoplight switch. In FIG. 9, case 1 that is cylindrical in shape is made of electrically insulating resin and has an open top surface. Sliding body 2 is housed in case 1 in a manner vertically movable. A plurality of fixed contacts 3 are planted in case 1 in a manner such that terminals 3A project out from bottom surface 1A.
A switch contact is configured in a manner such that movable contact 4 made of a conductive metal is in resilient contact with fixed contacts 3 by means of pressing spring 5 that is mounted between movable contact 4 and bottom surface 1A of case 1 in a slightly pressed state.
Also, return spring 6 is mounted in a slightly pressed state between a lower surface of sliding body 2 and bottom surface 1A of case 1 so as to urge sliding body 2 upward.
Furthermore, the bottom end of action rod 7 is inserted into hole 2A in the center of sliding body 2. Cover 8 covers the upper opening of case 1. A plurality of projections and depressions sections 7A are provided on the periphery of action rod 7, and the top end of action rod 7 projects upward from a through-hole in the center of cover 8.
Stoplight switch 10 is configured in a manner such that end portions of engagement spring 9 which is roughly U-shaped are supported by sliding body 2 while the slightly widened middle portion is in resilient contact with projections and depressions sections 7A of action rod 7.
Next, referring to an external view of FIG. 10, a description will be given on a method of mounting stoplight switch of this configuration on a vehicle.
In FIG. 10, brake pedal 11 is urged rightward by spring member 13 and the like.
Stoplight switch 10 is mounted by inserting into a mounting hole (not drawn) of mounting bracket 12 and secured by turning in an engaging section provided on cover 8. At this time, as action rod 7 is urged by return spring 6 as well as is positioned by engagement spring 9 in a manner projecting out from a predetermined position, it presses brake pedal 11 leftward.
Therefore, as it is not possible to adjust the length of action rod 7 as it is, brake pedal 11 is held with a hand so that it will not move leftward, and stoplight switch 10 is mounted on mounting bracket 12 in that state. This way, the front end of action rod 7 touches contact surface 11A of brake pedal 11 and is depressed.
For this reason, as sliding body 2 that supports action rod 7 with engagement spring 9 moves downward from the state illustrated in FIG. 9 while depressing return spring 6 and presses movable contact 4, movable contact 4 moves downward while depressing pressing spring 5 and detaches itself from fixed contacts 3 thus leaving the switch contacts in an “off” state.
Next, when the bottom end of sliding body 2 comes into contact with bottom surface 1A of case 1 through movable contact 4 thus making sliding body 2 unable to move downward any more, action rod 7 moves downward through hole 2A of sliding body 2 while expanding engagement spring 9 that is in resilient contact with projections and depressions sections 7A. When mounting is finished, engagement spring 9 comes into resilient contact with projections and depressions sections 7A at that position, and action rod 7 is held at a predetermined position of sliding body 2.
In summary, by mounting stoplight switch 10 on mounting bracket 12 in a state in which brake pedal 11 is being held, the switch contacts come to an “off” position and, at the same time, action rod 7 is depressed to a predetermined position thus enabling simultaneous adjustment of the length of action rod 7.
Subsequently, a connector or the like is fit to terminals 3A of fixed contacts 3 that project out from bottom surface 1A of case 1 for connection to a stoplight (not shown).
When brake pedal 11 is depressed in a state in which action rod 7 has been depressed thus making switch contact and stoplight “off”, as contact surface 11A is separated from action rod 7, sliding body 2 moves upward by the pressure of return spring 6. At the same time, movable contact 4 pressed by pressing spring 5 comes into resilient contact with fixed contacts 3 making switch contact “on” thus lighting the stoplight.
As a prior art literature relating to the invention of the present patent application, Japanese Patent Laid-Open Application No. H10-149736 is known.
However, when mounting stoplight switch 10 on a vehicle, the above-described conventional stoplight switch suffered a problem of requiring complicated and time-consuming work because the stoplight switch is mounted while adjusting the length of action rod 7 in a state in which brake pedal 11 is being held.